[dpdk-dev] [PATCH v2] app/testpmd: Document what the application does.

[Ben Pfaff <blp@ovn.org>]

I could not find anything in the documentation that says what
testpmd does.  This should save other people time trying to
figure that out in the future.

Signed-off-by: Ben Pfaff <blp@ovn.org>
---
v1->v2: Revise introduction instead of option documentation.
  Thanks to Thomas Monjalon for advice.

 doc/guides/testpmd_app_ug/intro.rst | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/doc/guides/testpmd_app_ug/intro.rst b/doc/guides/testpmd_app_ug/intro.rst
index 5d8d8cf4eb..1129f53c62 100644
--- a/doc/guides/testpmd_app_ug/intro.rst
+++ b/doc/guides/testpmd_app_ug/intro.rst
@@ -6,9 +6,13 @@ Introduction
 
 This document is a user guide for the ``testpmd`` example application that is shipped as part of the Data Plane Development Kit.
 
-The ``testpmd`` application can be used to test the DPDK in a packet forwarding mode
-and also to access NIC hardware features such as Flow Director.
-It also serves as a example of how to build a more fully-featured application using the DPDK SDK.
+``testpmd`` is a tool to test ethdev NIC features, including NIC
+hardware features such as Flow Director.  It receives packets on each
+configured port and forwards them.  By default, packets received on
+port 0 are forwarded to port 1, and vice versa, and similarly for
+ports 2 and 3, ports 4 and 5, and so on.  If an odd number of ports is
+configured, packets received on the last port are sent back out on the
+same port.
 
 The guide shows how to build and run the testpmd application and
 how to configure the application from the command line and the run-time environment.
-- 
2.31.1